Polaron

The neighboring electrons are pushed back due to the repulsion of charges of the same name, while the neighboring positive atomic cores are attracted.

The polarons denote special quasiparticles that are formed by charged particles due to the local polarization of the crystal lattice . The polaron is a fermionic quasiparticle in all cases and should not be confused with the polariton (a bosonic quasiparticle).

When electrons move through a crystal, they create a polarization in their environment due to their electrical charge (see picture). This “polarization cloud” moves together with the electron and causes an increase in the effective mass , especially in so-called polar crystals (e.g. with different ion charges ). In theoretical assumptions, independent quasiparticles called polarons are assigned to the deformations that are generated in this way.

Polarons can not only come from electrons, but also from protons , deuterons or muons . Furthermore, there are so-called magnetic polarons in magnetic crystals , which entrain a kind of magnetization cloud.

The electron-phonon interactions in the formation of Cooper pairs in superconductors of the first type can be modeled as polarons.

Individual evidence

1. ^ AS Alexandrov, Nevill Mott , High Temperature Superconductors And Other Superfluids, ISBN 0203211499 , p. 75, Google Books

Web links

• Condensed-matter physics: Repulsive polarons found nature.com, accessed May 24, 2012
• New particle: "Polaron" orf.at

literature

• Charles Kittel: Introduction to Solid State Physics . Oldenbourg Wissenschaftsverlag, 2005, ISBN 978-3-486-57723-5 , p. 459 .